The Prime Minister has defended his plans for a national identity register and ID cards.

At his regular monthly press conference in 10 Downing Street yesterday, Mr Blair said ID cards would add no more than about £30 to the cost of a biometric passport - equal to £3 for each of its ten years of validity.

And he said that the introduction of the cards would not only provide additional protection against organised crime, terrorism and illegal immigration, but would protect vulnerable people and make it easier to access services. The issue of ID cards was not a question of civil liberties but of using modern technology to deal with modern problems, he said.

Surveys had shown that the public does not "have a problem" with the use of CCTV cameras and anti-social behaviour orders to protect them from crime, or DNA testing to detect criminals, said Mr Blair.

And he added: "In the end, we have a modern world that we are living in, that has new and different types of crime.

"If we don't use technology in order to combat it, then we won't be fighting crime effectively."

Having a secure means of proving identity would assist the authorities in tackling benefit fraud, preventing NHS "health tourism" and stopping illegal working, said Mr Blair.

But it would also help ordinary law-abiding people with everyday tasks like opening a bank account, applying for a mortgage or notifying changes of address.

"I believe over time we will be able to show people not merely that this is an issue that is important for security, but it actually makes accessing services in modern life far easier for people," he said.

Mr Blair said ID cards would help Britain by making the nation's borders more secure; improving the protection of the most vulnerable; enabling better crime detection; and preventing fraud.

One in four criminals now use fake identities, and some terrorist suspects are known to have as many as 50 assumed identities.